Methods for fabricating a 3D NAND flash memory are disclosed. The method includes the steps of forming a hardmask pattern on the hardmask layer, and using the hardmask pattern to form apertures in the alternating layers by selectively plasma etching the alternating layers versus the hardmask layer using a hydrofluorocarbon etching gas selected from the group consisting of 1,1,1,3,3,3-hexafluoropropane (C.sub.3H.sub.2F.sub.6), 1,1,2,2,3,3-hexafluoropropane (iso-C.sub.3H.sub.2F.sub.6), 1,1,1,2,3,3,3-heptafluoropropane (C.sub.3HF.sub.7), and 1,1,1,2,2,3,3-heptafluoropropane (iso-C.sub.3HF.sub.7), wherein the first etching layer comprises a material different from that of the second etching layer.

Disclosed are compositions comprising HCFC-243db, HCFO-1233xf, HCFC-244db and/or HFO-1234yf and at least one additional compound. For the composition comprising 1234yf, the additional compound is selected from the group consisting of HFO-1234ze, HFO-1243zf, HCFC-243db, HCFC-244db, HFC-245cb, HFC-245fa, HCFO-1233xf, HCFO-1233zd, HCFC-253fb, HCFC-234ab, HCFC-243fa, ethylene, HFC-23, CFC-13, HFC-143a, HFC-152a, HFC-236fa, HCO-1130, HCO-1130a, HFO-1336, HCFC-133a, HCFC-254fb, CHF═CHCl, HFO-1141, HCFO-1242zf, HCFO-1223xd, HCFC-233ab, HCFC-226ba, and HFC-227ca. Compositions comprising HCFC-243db, HCFO-1233xf, and/or HCFC-244db are useful in processes to make HFO-1234yf. Compositions comprising HFO-1234yf are useful, among other uses, as heat transfer compositions for use in refrigeration, air-conditioning and heat pump systems.

Disclosed are compositions comprising HCFC-243db, HCFO-1233xf, HCFC-244db and/or HFO-1234yf and at least one additional compound. For the composition comprising 1234yf, the additional compound is selected from the group consisting of HFO-1234ze, HFO-1243zf, HCFC-243db, HCFC-244db, HFC-245cb, HFC-245fa, HCFO-1233xf, HCFO-1233zd, HCFC-253fb, HCFC-234ab, HCFC-243fa, ethylene, HFC-23, CFC-13, HFC-143a, HFC-152a, HFC-236fa, HCO-1130, HCO-1130a, HFO-1336, HCFC-133a, HCFC-254fb, CHF═CHCl, HFO-1141, HCFO-1242zf, HCFO-1223xd, HCFC-233ab, HCFC-226ba, and HFC-227ca. Compositions comprising HCFC-243db, HCFO-1233xf, and/or HCFC-244db are useful in processes to make HFO-1234yf. Compositions comprising HFO-1234yf are useful, among other uses, as heat transfer compositions for use in refrigeration, air-conditioning and heat pump systems.

The present invention relates to a process for purifying 1,1,1,2,3-pentafluoropropane, comprising the steps of: i) providing a composition A1 comprising 1,1,1,2,3-pentafluoropropane and 1,1,1,3-tetrafluoropropane; ii) purifying, preferably distilling, said composition A1 under conditions that are sufficient to form at least two streams including a first stream comprising 1,1,1,2,3-pentafluoropropane and a second stream comprising 1,1,1,3-tetrafluoropropane. The present invention also relates to a process for producing 2,3,3,3-tetrafluoropropene and a composition comprising 2,3,3,3-tetrafluoropropene.

The present invention relates to a process for purifying 1,1,1,2,3-pentafluoropropane, comprising the steps of: i) providing a composition A1 comprising 1,1,1,2,3-pentafluoropropane and 1,1,1,3-tetrafluoropropane; ii) purifying, preferably distilling, said composition A1 under conditions that are sufficient to form at least two streams including a first stream comprising 1,1,1,2,3-pentafluoropropane and a second stream comprising 1,1,1,3-tetrafluoropropane. The present invention also relates to a process for producing 2,3,3,3-tetrafluoropropene and a composition comprising 2,3,3,3-tetrafluoropropene.

The present invention relates to a process for purifying 1,1,1,2,3-pentafluoropropane, comprising the steps of: i) providing a composition A1 comprising 1,1,1,2,3-pentafluoropropane and 1,1,1,3-tetrafluoropropane; ii) purifying, preferably distilling, said composition A1 under conditions that are sufficient to form at least two streams including a first stream comprising 1,1,1,2,3-pentafluoropropane and a second stream comprising 1,1,1,3-tetrafluoropropane. The present invention also relates to a process for producing 2,3,3,3-tetrafluoropropene and a composition comprising 2,3,3,3-tetrafluoropropene.

A process for treating a composition comprising one or more desired (hydro)halocarbons and one or more undesired halogenated hydrocarbon containing impurities so as to reduce the concentration of at least one undesired halogenated hydrocarbon containing impurity, the process comprising contacting the composition with an adsorbent comprising a carbon molecular sieve.

A process for treating a composition comprising one or more desired (hydro)halocarbons and one or more undesired halogenated hydrocarbon containing impurities so as to reduce the concentration of at least one undesired halogenated hydrocarbon containing impurity, the process comprising contacting the composition with an adsorbent comprising a carbon molecular sieve.

A process for treating a composition comprising one or more desired (hydro)halocarbons and one or more undesired halogenated hydrocarbon containing impurities so as to reduce the concentration of at least one undesired halogenated hydrocarbon containing impurity, the process comprising contacting the composition with an adsorbent comprising a carbon molecular sieve.

An object of the present invention is to extend the catalyst lifetime in a method for producing fluoromethane by pyrolyzing fluorine-containing methyl ether in the presence of a catalyst. The present invention provides a method for producing fluoromethane by pyrolyzing a fluorine-containing methyl ether represented by Formula (1) in a gas phase in the presence of a catalyst,

the pyrolysis being conducted at a moisture concentration of 100 ppm or less,

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wherein R.sup.1 and R.sup.2 are identical or different, and each represents a substituted or unsubstituted straight or branched monovalent aliphatic hydrocarbon group, substituted or unsubstituted monovalent aromatic hydrocarbon group, substituted or unsubstituted monovalent cyclic aliphatic hydrocarbon group, hydrogen atom, or halogen atom.